The Burden of and Risk Factors for Trachoma in Selected Districts of Zimbabwe: Results of 16 Population-Based Prevalence Surveys

Figures & data

Table 1. Districts selected for the first two phases of trachoma mapping in Zimbabwe, 2014–2015.

Province	Districts
	Phase 1	Phase 2
Manicaland	Chipinge
Mashonaland East	Mudzi	Mutoko, Uzumba Maramba Pfungwe
Mashonaland Central	Mbire	Rushinga, Centinary
Mashonaland West	Kariba	Hurungwe,
Midlands	Gokwe North	Gokwe South
Masvingo	Chivi
Matabeleland South	Magwe
Matabeleland North	Binga	Lupane, Hwange

Table 2. Sampling by district, Global Trachoma Mapping Project, Zimbabwe, 2014–2015.

Province	District	Households (n)	Individuals
			Registered (n)	Examined (n, %)	Absent (n, %)	Refused (n, %)	Other (n, %)
Manicaland	Chipinge	1073	3827	3735 (97.6)	53 (1.4)	39 (1)
Mashonaland Central	Mbire	1079	2800	2749 (98.2)	33 (1.2)	18 (0.6)
	Rushinga	1078	2817	2803 (99.5)	11 (0.4)	3 (0.1)
	Centenary	1076	2708	2706 (99.9)	0 (0)	2 (0.1)
Mashonaland East	Mudzi	1086	3590	3326 (92.6)	253 (7)	11 (0.3)
	Mutoko	1126	3416	3377 (98.9)	37 (1.1)	2 (0.1)
	Uzumba Maramba Pfungwe	1074	3351	3255 (97.1)	29 (0.9)	67 (2)
Mashonaland West	Kariba	1063	3630	3285 (90.5)	338 (9.3)	7 (0.2)
	Hurungwe	1079	3504	3307 (94.4)	193 (5.5)	4 (0.1)
Masvingo	Chivi	1063	3074	2592 (84.3)	473 (15.4)	3 (0.1)	6^a(0.2)
Matabeleland North	Binga	1072	3376	2928 (86.7)	383 (11.3)	65 (1.9)
	Lupane	1096	3882	3826 (98.6)	37 (1)	15 (0.4)	4^b(0.1)
Matabeleland South	Mangwe	1097	3664	3602 (98.3)	58 (1.6)	4 (0.1)
	Hwange	1079	4215	4155 (98.6)	41 (1)	18 (0.4)	1^c(0)
Midlands	Gokwe north	1082	4583	4069 (88.8)	504 (11)	9 (0.2)	1^d(0)
	Gokwe South	1076	3555	3496 (98.3)	57 (1.6)	1 (0)	1^e(0)
Totals		17,299	55,992	53,211 (95)	2500 (4.5)	268 (0.5)	13(0)

^aDisabled.

^bThree recently deceased, three blind.

^cUnable to follow instructions.

^dTwo blind, one unable to examine due to facial burns, one reason not given.

^eRecent reaction to eye medication prevented examination.

Table 3. Examination results, Global Trachoma Mapping Project, Zimbabwe, 2014–2015.

Province	District	Age (years)
		1–9				10–14				15 years or greater
		n	TF^a	TI^b	Trichiasis	n	TF	TI	Trichiasis	n	TF	TI	Trichiasis	Total
Manicaland	Chipinge	1330	64	3	0	553	33	1	0	1852	53	5	6	3735
Mashonaland Central	Centenary	799	229	22	0	263	17	9	1	1644	6	11	16	2706
	Mbire	710	65	57	0	210	2	5	0	1829	5	12	41	2749
	Rushinga	889	99	13	0	328	16	0	0	1586	13	0	10	2803
Mashonaland East	Mudzi	1144	92	0	0	505	17	1	0	1677	57	7	10	3326
	Mutoko	1068	83	9	0	471	32	3	0	1838	32	20	3	3377
	Uzumba Maramba Pfungwe	1007	73	0	0	455	27	1	0	1793	49	7	14	3255
Mashonaland West	Hurungwe	1023	27	2	0	411	6	0	0	1873	10	0	3	3307
	Kariba	1096	68	2	0	403	7	0	0	1786	3	0	7	3285
Masvingo	Chivi	1169	15	13	0	167	1	1	0	1256	1	0	3	2592
Midlands	Gokwe north	1292	101	0	0	598	20	0	1	2179	23	5	22	4069
	Gokwe South	1193	206	15	0	455	12	3	0	1848	11	2	21	3496
Matabeleland North	Binga	1156	130	14	0	7	2	0	1	1765	6	2	58	2928
	Hwange	1634	45	4	0	194	3	0	0	2327	1	0	7	4155
	Lupane	1546	186	13	0	134	8	1	0	2146	71	36	15	3826
Matabeleland South	Mangwe	1140	43	10	0	342	22	5	0	2120	14	5	63	3602
	Totals	18,196	1526	177	0	5496	225	30	3	29,519	355	112	299	53,211

^aTF, Trachomatous inflammation–follicular.

^bTI, Trachomatous inflammation–intense.

Table 4. Estimated population-level prevalence of trachomatous inflammation–follicular (TF) in children aged 1–9 years by district, Global Trachoma Mapping Project, Zimbabwe, 2014–2015.

Province	District	TF Unadj^a	TF Adj^b	95% CI^c
Manicaland	Chipinge	4.8	4.3	[3.1–5.5]
Mashonaland Central	Centenary	28.7	27.8	[21.6–35.5]
	Mbire	9.2	7.8	[5.3–11]
	Rushinga	11.1	9.4	[7.1–11.4]
Mashonaland East	Mudzi	8.0	8.2	[6.5–10]
	Mutoko	7.8	6.7	[4.4–9.7]
	Uzumba Maramba Pfungwe	7.2	6.9	[5.0–8.8]
Mashonaland West	Hurungwe	2.6	2.4	[1.2–4.1]
	Kariba	6.2	5.5	[3.9–7.5]
Masvingo	Chivi	1.3	1.5	[0.7–2.3]
Midlands	Gokwe north	7.8	7.5	[5.1–10.1]
	Gokwe South	17.3	16.5	[13.0–20.1]
Matabeleland North	Binga	11.2	9.6	[6.3–13.8]
	Hwange	2.8	2.2	[1.3–3.1]
	Lupane	12.0	11.9	[8.0–15.2]
Matabeleland South	Mangwe	3.8	3.2	[2.0–4.3]

^aUnadjusted (crude) prevalence estimate.

^bAdjusted for age in 1-year age groups using the latest available census data; Districts with a TF prevalence where mass distribution of azithromycin is recommended are highlighted in bold.

^c95% confidence interval estimated by bootstrapping the adjusted cluster-level estimates to account for the clustered design of the sampling.

Table 5. Recommendations for implementation of components of the SAFE strategy based on prevalence of trachomatous–inflammation follicular (TF) and trichiasis, Zimbabwe, 2014–2015.

Prevalence	Names of districts (n)	Recommendation^a
TF prevalence in 1–9 years (%)
< 5%	Chipinge, Chivi, Mangwe, Hurungwe, Hwange (n = 5)	No A, F, E needed for elimination of trachoma as a public health problem
≥ 5% and < 10%	Mudzi, Mbire, Kariba, Gokwe North, Mutoko, UMP, Rushinga, Binga (n = 8)	Targeted A as appropriate to program needs (e.g., 1 round of MDA); Conduct F,E
≥ 10% and < 30%	Centenary, Lupane, Gokwe South (n = 3)	Implementation at district; 3 rounds of A (MDA) plus implementation of F and E, then re-survey
Trichiasis prevalence in those aged 15 years or greater (%)
< 0.2	Chivi, Kariba, Hwange, Mutoko, Rushinga, Hurungwe (n = 6)	A public health approach to delivery of trichiasis surgery not necessary for elimination of trachoma as a public health problem
≥ 0.2	Mudzi, Chipinge, UMP, Lupane, Gokwe South, Centenary, Gokwe North, Mangwe, Mbire and Binga (n = 10)	Scaling up of efforts to train trichiasis surgeons and implementation of community-based case detection and management

^aS, Trichiasis Surgery; A, Antibiotics; F, Facial cleanliness; E, Environmental improvement.

Table 6. Estimated population-level prevalence of trichiasis and estimated trichiasis surgery backlogs by district, Global Trachoma Mapping Project, Zimbabwe, 2014–2015.

Province	District	Estimated population ≥15 years^a	Trichiasis unadj^b (%)	Trichiasis adj^c (%)	95% CI^d	Estimated trichiasis cases^e
Manicaland	Chipinge	153,948	0.32	0.32	[0–0.6]	493
Mashonaland Central	Centenary	63,256	0.97	0.53	[0.3–0.8]	335
	Mbire	42,438	2.24	1.36	[0.8–1.9]	577
	Rushinga	38,142	0.63	0.12	[0–0.2]	46
Mashonaland East	Mudzi	68,645	0.6	0.23	[0–0.4]	158
	Mutoko	75,278	0.16	0.12	[0–0.3]	90
	Uzumba Maramba Pfungwe	58,012	0.78	0.34	[0.1–0.6]	197
Mashonaland West	Hurungwe	169,586	0.16	0.05	[0–0.1]	85
	Kariba	21,312	0.39	0.13	[0–0.3]	28
Masvingo	Chivi	85,540	0.24	0.16	[0–0.4]	137
Midlands	Gokwe north	123,818	1.01	0.69	[0.4–1]	854
	Gokwe South	157,627	1.14	0.42	[0.2–0.6]	662
Matabeleland North	Binga	71,654	3.29	1.81	[1.2–2.6]	1297
	Hwange	32,285	0.3	0.12	[0–0.2]	39
	Lupane	51,598	0.7	0.35	[0.1–0.6]	181
Matabeleland South	Mangwe	34,112	2.97	0.96	[0.6–1.3]	327
	Total	1,247,251	-	-	-	5506

^aPopulation Census 2012, Zimbabwe National Statistics Agency.

^bUnadjusted (crude) prevalence estimate.

^cAdjusted for sex and age in 5-year age groups using the latest available census data.

^d95% confidence interval estimated by bootstrapping the adjusted cluster-level estimates to account for the clustered design of the sampling.

^eEstimated by applying the adjusted trichiasis prevalence to the estimated rural population aged 15 years or greater in each district.

Table 7. Multilevel univariable associations with trachomatous inflammation–follicular (TF) in children aged 1–9 years, Global Trachoma Mapping Project, Zimbabwe, 2014–2015.

Variable		n	TF%	Odds Ratio	95% CI	p-value^a
Individual
Sex	Male	9231	8.6	1	–
	Female	8965	8.2	0.97	0.87–1.08	0.5936
Age	1–5	11,302	9.6	1.54	1.36–1.73	<0.0001
	6–9	6894	6.5	1	–
Household
Number of household inhabitants	1–5	13,412	8.4	1
	≥6	4784	8.4	1.0	0.82–1.22	0.938
Number of children in household	1–3	16,002	8.1	1
	≥4	2194	10.5	1.42	1.14–1.77	0.0016
Surface water drinking source	Yes	2095	8.1	0.97	0.79–1.20	0.8193
	No	16,101	8.4	1
Time to drinking water source	<30 minutes	9229	7.6	1
	≥30 minutes	8967	9.2	1.30	1.12–1.53	0.0008
Surface water washing source	Yes	2444	7.6	0.88	0.70–1.12	0.3134
	No	15,752	8.5	1
Time to washing water source	All washing done at source	194	2.1	0.19	0.06–0.62	0.0405
	<30 minutes	9126	7.8	1	–
	≥30 minutes	8876	9.2	1.27	1.09–1.49
Household open defecation	Yes	9413	10.3	1.94	1.66–2.28	<0.0001
	No	8783	6.4	1
Household unimproved latrine	Yes	10,999	10.1	2.19	1.85–2.59	<0.0001
	No	7197	5.8	1
Household unimproved washing source	Yes	7387	9.9	1.51	1.29–1.77	<0.0001
	No	10,809	7.4	1
Cluster-level geoclimate^b
Altitude	<750 m	6258	9.9	1
	≥750 m	11,925	7.6	0.70	0.59–0.82	<0.0001
Annual rainfall	<600 mm	2797	4	1
	≥600 mm	15,399	9.2	3.11	2.37–4.08	<0.0001
Annual mean temperature	<23°C	15,033	7.8	1
	≥23°C	3163	11.3	1.67	1.38–2.02	<0.0001
Annual maximum temperature	<35°C	16,353	8.8	1
	≥35°C	1843	4.8	0.45	0.33–0.61	<0.0001

^aWald’s test.

^bEstimated from the mean of household GPS coordinates at cluster-level, with climate variables extracted from Bioclim rasters (worldclim.org) at 2.5 arc-minutes (~5km) resolution.

Table 8. Independent predictors of trachomatous inflammation–follicular (TF) in children aged 1–9 years, Global Trachoma Mapping Project, Zimbabwe, 2014–2015.

Variable	Odds Ratio	p-value^a
Age 1–5 years	1.7	<0.0001
≥4 children aged 1–9 years living in the household	1.7	0.014
Household use of open defecation	1.9	0.0002
Altitude ≥750 metres	0.6	<0.0001
Annual rainfall ≥600 mm	2.8	<0.0001
Annual maximum temperature ≥35°C	0.3	<00001

^aLikelihood ratio test of inclusion/exclusion of variable in final model.

Figure 1. Estimated prevalence of trachomatous inflammation–follicular (TF) among children aged 1–9 years, by district, Global Trachoma Mapping Project, Zimbabwe, 2014–2015.

Figure 2. Adjusted prevalence of trichiasis in adults aged 15 years or greater, by district, Global Trachoma Mapping Project, Zimbabwe, 2014–2015.